Quantum carrier capture and release effects on optical bistability in multiple quantum well (MQW) lasers are studied using the well barrier hole burning model. The ratio of carrier capture to release time (h) is varied and the hysterisis width, transient behavior are analysed by simulating the equivalent circuit of MQW bistable laser using circuit simulation program Pspice. The hysterisis width is found to increase with an increase in h. From the time response, improved damping and increased turn on delay are observed in switching characteristics for higher value of h.